This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Certain phosphorus compounds are highly effective at suppressing fires, which is why they are widely used in flame retardants. Phosphorus, however, is a finite resource.
Estimates suggest it could be depleted within the next 50–300 years. That is why, as part of the ScaleAmP project, a research team is working to extract phosphorus from corn steep liquor, a byproduct of starch production. The team brings together researchers from the Fraunhofer Institute for Wood Research, Wilhelm-Klauditz-Institut WKI, and the Fraunhofer Institute for Applied Polymer Research IAP.
Together with partners, they are using corn steep liquor to develop a flame retardant for use in wood-plastic composites (WPCs) and other biomaterials. Their work is published in the journal RSC Sustainability. The phytic acid that can be extracted from corn steep liquor, also known as phytate, is a natural source of phosphorus.
It is found in large quantities in plants such as corn, wheat bran, soybeans and rice. "Commercial halogenated flame retardants are highly effective, but they are also toxic and environmentally harmful. To help protect the climate and meet regulatory requirements, industry is stepping up its transition to sustainable phosphorus-based flame retardants," says Matthias Bischoff, a research scientist at Fraunhofer WKI.
"We are supporting this trend by using the phytic acid in corn steep liquor as an active ingredient in flame retardants and developing a cost-effective process for producing the flame retardant on a technical scale." The research partners are demonstrating potential applications and flame retardant properties using a wood-plastic composite material, which is used in construction and in the automotive and furniture industries. Thanks to its high phosphorus content, phytic acid has strong potential as a flame retardant, especially in the form of ammonium phytates. When heated, the molecule forms an insulating carbon layer that cuts off the fire's oxygen supply.
However, for effective flame retardancy, phytic acid requires a source of nitrogen to form a synergistic compound with phosphorus. Pure phytic acid is ineffective and has a very low pH, making it incompatible with most materials. One challenge the researchers faced was developing an efficient, cost-effective process to purify phytic acid, which is highly water-soluble.
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